Microsoft Application Virtualization (also known as App-V;[1] formerly Microsoft SoftGrid)[2] is an application virtualization and application streaming solution from Microsoft. It was acquired by Microsoft during the acquisition of Boston, Massachusetts-based Softricity (SoftwareWow!) on July 17, 2006.[3] Softgrid represents Microsoft's entry to a new avenue of virtualization product, alongside their existing Hyper-V package, Microsoft Virtual Server, Microsoft Virtual PC, and other products newly announced in 2006, such as System Center Virtual Machine Manager, the latter of which is designed for "Datacenter Virtualization".[4]
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Microsoft Application Virtualization (MS App-V) platform allows applications to be deployed in real-time to any client from a virtual application server. It removes the need for local installation of the applications. Instead, only the App-v client needs to be installed on the client machines. All application data is permanently stored on the virtual application server. Whichever software is needed is either streamed or locally cached from the application server on demand and run locally. The App-V stack sandboxes the execution environment so that the application does not make changes to the client itself (OS File System and/or Registry). App-V applications are also sandboxed from each other, so that different versions of the same application can be run under App-V concurrently. This approach enables any application to be delivered without making any changes to its code lun.
MS App-V thus allows centralized installation and management of deployed applications. It supports policy based access control; administrators can define and restrict access to the applications by certain users by defining policies governing the usage. App-V can require that applications not be run 'cached' from workstations, or require that 'cached' App-V applications routinely update license information from the App-V server, enforcing license compliance. These policies are centrally applied on the application repository. App-V also allows copy of the applications across multiple application servers for better scalability and fault tolerance, and also features a tracking interface to track the usage of the virtualized application.
The App-V client presents the user with a list of applications, to which the user has access. The user can then launch a virtualized instance of the application. Depending on the configuration, the systems administrator can be either notified of the action via email or it can require an explicit confirmation from the administrator for the application to start streaming and initialize or it can just simply check the Active Directory for the user's rights and stream the application to the user if it is authorized to run the application. The App-V client can also install local shortcuts that bootstrap the process of launching individual virtualized software instances.
Although App-V is best known for being deployed using the dedicated App-V Management infrastructure, these days Microsoft offers three deployment options. These three options are significantly different from an architectural standpoint: Dedicated App-V Management Server, Shared System Center Configuration Manager Architecture, and "Stand-alone" Mode wherein the application may be delivered manually.
The App-V system architecture is composed of the following components:
In 2009 Microsoft offered a new way to implement App-V with enhancements to System Center Configuration Manager. System Center Configuration Manager Architecture consists of the following components:
The App-V clients may also be used in a "stand-alone" mode without either of the server infrastructures previously described. In this case, the sequenced packages are delivered using an external technique, such as an Electronic Software Delivery system or manual deployment.
App-V Application Virtualization is composed mainly of two components – SystemGuard and App-V Sequencer. SystemGuard tracks and analysis configuration repositories and resources used by the application and intercepts the use of these resources, redirecting them to the virtualized instances of the resources. Virtualized resources include virtualized data such as user profile information and data; virtualized system services, such as COM controls, windows services and copy/paste abilities; and virtualized configuration repositories like registry hives and INI files. Not all applications that run as a service can be virtualized, although these limitations may change in future product versions. The virtualized instances are created in the runtime sandbox which hosts the virtualized instance, representing the resources of the actual client system the application is being executed on. Thus the application is decoupled from the resources of the system the application is installed on. Each application, or multiple instances of the same application, is run in its own virtual sandbox, each with its own set of virtual resources. The SystemGuard runtime environments can include specific dependencies such as DLL files as well. Multiple SystemGuard runtime environments can be in execution simultaneously.
App-V sequencer is the component which packages an application for virtualization and streaming. It analyzes the application for the resources that it requires and creates the SystemGuard runtime environment that it will require. It also packages specific DLL files that it might require at the client side. It then packs all the application code and data into App-V's proprietary format that makes it more suitable for streaming. Individual libraries are packed separately so that each library can be streamed as required, rather than having the client to download the entire application at the beginning. Most importantly, the sequencer translates file and reqistry references into user, machine, and operating system neutral references. This often allows limited portability of sequenced applications between OS versions.
At the client, when a streaming request is made to an App-V server, portions of the entire sequencer package are transferred to the client, who unpacks and initializes the SystemGuard environment and hosts the application inside it (with System Center Configuration Manager and the stand-alone client, the entire package contents are transferred). Each package is cached by the client for the duration of the application session. User settings are stored in the local system itself.
Virtualized application packages can also locally reside at the client computer, thus eliminating the need of application server and streaming. Microsoft Systems Management Server can be used to push these packages to the client computer in the absence of a virtual application server. In this scenario, the App-V SMS Connector can be used to locally manage the application packages.
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